A broadband wireless access (BWA) technique is a technique for providing high-speed transmission for wireless network and data network in a wide region. After a worldwide interoperability for microwave access (WiMAX) standard (IEEE 802.16d/e) has been issued, the transmission speed of the BWA technique is greatly increased.
FIG. 1 is a schematic architectural view of a system between a central office and base stations of a conventional BWA system. Referring to FIG. 1, in the BWA technique, during the hardware construction, dedicated lines 93a and 93b must be respectively configured between a central office 90 and a plurality of base stations 92a and 92b. The architecture shown in FIG. 1 is a point-to-multipoint (one-to-many) architecture.
A passive optical network (PON) is a point-to-multipoint optical fiber network system, which is usually used to connect an optical line terminal (OLT) located on the central office provided by a service provider and a plurality of optical network units (ONUs) (also called optical network terminals at user ends) near the user ends. FIG. 2 is a schematic architectural view of a system between an OLT 94 and ONUs 96a and 96b of a conventional PON system. Referring to FIG. 2, in the PON, the optical splitting is realized by using a passive element 97 (an un-powered element). Such passive optical splitting element is commonly an optical splitter.
Through comparing FIG. 1 with FIG. 2, it can be clearly known that, the PON system architecture and the BWA system architecture both belong to the one-to-many configuration architecture.
Next, the infrastructure of the optical fiber network is constructed much earlier than that of the BWA network, so that a part of the people involved in the broadband wireless industry cooperate with the PON industry, and thus, base stations of the BWA network are disposed on the positions of the ONUs of the PON, and the central office is disposed on the position of the OLT of the PON. The optical fiber network and the BWA network both transfer data at the same time by adopting the same PON. In this manner, the bandwidth of the PON is fully utilized.
The above technique for providing wireless communication in the PON has been disclosed in US Patent Publication No. 2008/0063397, filed on Mar. 13, 2008, and entitled “System and Method for Providing Wireless over a Passive Optical Network”. In addition, similar techniques may be known with reference to the following papers:
The paper issued by D. Qian, J. Hu, P. Ji, T. Wang, and M. Cvijetic (with reference to “10-Gb/s OFDMA-PON for Delivery of Heterogeneous Services”, OFC 2008), the paper issued by M. Bakaul, A. Nirmalathas, C. Lim, D Novak, and R. Waterhouse (with reference to “Hybrid Multiplexing of Multiband Optical Access Technologies Towards an Integrated DWDM Network”, IEEE Photonics Technology Letters, vol. 18, no. 21, November 2006, pp. 2311-2313), and the paper issued by M. Crisp, S. Li, A. Watts, R. Penty, and I. White (with reference to “Uplink and Downlink Coverage Improvements of 802.11g Signals Using a Distributed Antenna Network”, IEEE Journal of Lightwave Technology, vol. 25, no. 11, November 2007, pp. 3388-3395).